htparse.c

用于linux和其他unix下面的

**		/etc/junk/./fred	becomes /etc/junk/fred
**
**	but we should NOT change
**		http://fred.xxx.edu/../..
**
**	or	../../albert.html
*/
PUBLIC void HTSimplify ARGS1(
	char *,		filename)
{
    char *p;
    char *q, *q1;

    if (filename == NULL)
	return;

    if (!(filename[0] && filename[1]) ||
	filename[0] == '?' || filename[1] == '?' || filename[2] == '?')
	return;

    if (strchr(filename, '/') != NULL) {
	for (p = (filename + 2); *p; p++) {
	    if (*p == '?') {
		/*
		**  We're still treating a ?searchpart as part of
		**  the path in HTParse() and scan(), but if we
		**  encounter a '?' here, assume it's the delimiter
		**  and break.	We also could check for a parameter
		**  delimiter (';') here, but the current Fielding
		**  draft (wisely or ill-advisedly :) says that it
		**  should be ignored and collapsing be allowed in
		**  it's value).  The only defined parameter at
		**  present is ;type=[A, I, or D] for ftp URLs, so
		**  if there's a "/..", "/../", "/./", or terminal
		**  '.' following the ';', it must be due to the
		**  ';' being an unescaped path character and not
		**  actually a parameter delimiter. - FM
		*/
		break;
	    }
	    if (*p == '/') {
		if ((p[1] == '.') && (p[2] == '.') &&
		    (p[3] == '/' || p[3] == '?' || p[3] == '\0')) {
		    /*
		    **	Handle "../", "..?" or "..".
		    */
		    for (q = (p - 1); (q >= filename) && (*q != '/'); q--)
			/*
			**  Back up to previous slash or beginning of string.
			*/
			;
		    if ((q[0] == '/') &&
			(strncmp(q, "/../", 4) &&
			 strncmp(q, "/..?", 4)) &&
			!((q - 1) > filename && q[-1] == '/')) {
			/*
			**  Not at beginning of string or in a
			**  host field, so remove the "/xxx/..".
			*/
			q1 = (p + 3);
			p = q;
			while (*q1 != '\0')
			    *p++ = *q1++;
			*p = '\0';		/* terminate */
#ifdef NOTDEFINED
			/*
			**  Make sure filename has at least one slash.
			*/
			if (*filename == '\0') {
			    *filename = '/';
			    *(filename + 1) = '\0';
			}
#endif /* NOTDEFINED */
			/*
			**  Start again with previous slash.
			*/
			p = (q - 1);
		    }
		} else if (p[1] == '.' && p[2] == '/') {
		    /*
		    **	Handle "./" by removing both characters.
		    */
		    q = p;
		    q1 = (p + 2);
		    while (*q1 != '\0')
		       *q++ = *q1++;
		    *q = '\0';		/* terminate */
		    p--;
		} else if (p[1] == '.' && p[2] == '?') {
		    /*
		    **	Handle ".?" by removing the dot.
		    */
		    q = (p + 1);
		    q1 = (p + 2);
		    while (*q1 != '\0')
		       *q++ = *q1++;
		    *q = '\0';		/* terminate */
		    p--;
		} else if (p[1] == '.' && p[2] == '\0') {
		    /*
		    **	Handle terminal "." by removing the character.
		    */
		    p[1] = '\0';
		}
	    }
	}
	if (p >= filename + 2 && *p == '?' && *(p-1)  == '.') {
	    if (*(p-2) == '/') {
		/*
		**  Handle "/.?" by removing the dot.
		*/
		q = p - 1;
		q1 = p;
		while (*q1 != '\0')
		    *q++ = *q1++;
		*q = '\0';
	    } else if (*(p-2) == '.' &&
		       p >= filename + 4 && *(p-3) == '/' &&
		       (*(p-4) != '/' ||
			(p > filename + 4 && *(p-5) != ':'))) {
		    /*
		    **	Handle "xxx/..?"
		    */
		for (q = (p - 4); (q > filename) && (*q != '/'); q--)
			/*
			**  Back up to previous slash or beginning of string.
			*/
		    ;
		if (*q == '/') {
		    if (q > filename && *(q-1) == '/' &&
			!(q > filename + 1 && *(q-1) != ':'))
			return;
		    q++;
		}
		if (strncmp(q, "../", 3) && strncmp(q, "./", 2)) {
			/*
			**  Not after "//" at beginning of string or
			**  after "://", and xxx is not ".." or ".",
			**  so remove the "xxx/..".
			*/
		    q1 = p;
		    p = q;
		    while (*q1 != '\0')
			*p++ = *q1++;
		    *p = '\0';		/* terminate */
		}
	    }
	}
    }
}

/*	Make Relative Name.					HTRelative()
**	-------------------
**
** This function creates and returns a string which gives an expression of
** one address as related to another.  Where there is no relation, an absolute
** address is retured.
**
**  On entry,
**	Both names must be absolute, fully qualified names of nodes
**	(no anchor bits)
**
**  On exit,
**	The return result points to a newly allocated name which, if
**	parsed by HTParse relative to relatedName, will yield aName.
**	The caller is responsible for freeing the resulting name later.
**
*/
PUBLIC char * HTRelative ARGS2(
	CONST char *,	aName,
	CONST char *,	relatedName)
{
    char * result = NULL;
    CONST char *p = aName;
    CONST char *q = relatedName;
    CONST char * after_access = NULL;
    CONST char * path = NULL;
    CONST char * last_slash = NULL;
    int slashes = 0;

    for (; *p; p++, q++) {	/* Find extent of match */
	if (*p != *q)
	    break;
	if (*p == ':')
	    after_access = p+1;
	if (*p == '/') {
	    last_slash = p;
	    slashes++;
	    if (slashes == 3)
		path=p;
	}
    }

    /* q, p point to the first non-matching character or zero */

    if (!after_access) {			/* Different access */
	StrAllocCopy(result, aName);
    } else if (slashes < 3){			/* Different nodes */
	StrAllocCopy(result, after_access);
    } else if (slashes == 3){			/* Same node, different path */
	StrAllocCopy(result, path);
    } else {					/* Some path in common */
	int levels = 0;
	for (; *q && (*q != '#'); q++)
	    if (*q == '/')
		levels++;
	result = typecallocn(char, 3*levels + strlen(last_slash) + 1);
	if (result == NULL)
	    outofmem(__FILE__, "HTRelative");
	result[0] = '\0';
	for (; levels; levels--)
	    strcat(result, "../");
	strcat(result, last_slash+1);
    }
    CTRACE((tfp,
	"HTparse: `%s' expressed relative to\n	 `%s' is\n   `%s'.\n",
		aName, relatedName, result));
    return result;
}

/*		Escape undesirable characters using %		HTEscape()
**		-------------------------------------
**
**	This function takes a pointer to a string in which
**	some characters may be unacceptable unescaped.
**	It returns a string which has these characters
**	represented by a '%' character followed by two hex digits.
**
**	Unlike HTUnEscape(), this routine returns a calloced string.
*/
PRIVATE CONST unsigned char isAcceptable[96] =

/*	Bit 0		xalpha		-- see HTFile.h
**	Bit 1		xpalpha		-- as xalpha but with plus.
**	Bit 3 ...	path		-- as xpalphas but with /
*/
    /*	 0 1 2 3 4 5 6 7 8 9 A B C D E F */
    {	 0,0,0,0,0,0,0,0,0,0,7,6,0,7,7,4,	/* 2x	!"#$%&'()*+,-./  */
	 7,7,7,7,7,7,7,7,7,7,0,0,0,0,0,0,	/* 3x  0123456789:;<=>?  */
	 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,	/* 4x  @ABCDEFGHIJKLMNO  */
	 7,7,7,7,7,7,7,7,7,7,7,0,0,0,0,7,	/* 5X  PQRSTUVWXYZ[\]^_  */
	 0,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,	/* 6x  `abcdefghijklmno  */
	 7,7,7,7,7,7,7,7,7,7,7,0,0,0,0,0 };	/* 7X  pqrstuvwxyz{|}~	DEL */

PRIVATE char *hex = "0123456789ABCDEF";
#define ACCEPTABLE(a)	( a>=32 && a<128 && ((isAcceptable[a-32]) & mask))

PUBLIC char * HTEscape ARGS2(
	CONST char *,	str,
	unsigned char,	mask)
{
    CONST char * p;
    char * q;
    char * result;
    int unacceptable = 0;
    for (p = str; *p; p++)
	if (!ACCEPTABLE(UCH(TOASCII(*p))))
	    unacceptable++;
    result = typecallocn(char, p-str + unacceptable + unacceptable + 1);
    if (result == NULL)
	outofmem(__FILE__, "HTEscape");
    for (q = result, p = str; *p; p++) {
	unsigned char a = TOASCII(*p);
	if (!ACCEPTABLE(a)) {
	    *q++ = HEX_ESCAPE;	/* Means hex commming */
	    *q++ = hex[a >> 4];
	    *q++ = hex[a & 15];
	}
	else *q++ = *p;
    }
    *q++ = '\0';			/* Terminate */
    return result;
}

/*	Escape undesirable characters using % but space to +.	HTEscapeSP()
**	-----------------------------------------------------
**
**	This function takes a pointer to a string in which
**	some characters may be unacceptable unescaped.
**	It returns a string which has these characters
**	represented by a '%' character followed by two hex digits,
**	except that spaces are converted to '+' instead of %2B.
**
**	Unlike HTUnEscape(), this routine returns a calloced string.
*/
PUBLIC char * HTEscapeSP ARGS2(
	CONST char *,	str,
	unsigned char,	mask)
{
    CONST char * p;
    char * q;
    char * result;
    int unacceptable = 0;
    for (p = str; *p; p++)
	if (!(*p == ' ' || ACCEPTABLE(UCH(TOASCII(*p)))))
	    unacceptable++;
    result = typecallocn(char, p-str + unacceptable + unacceptable + 1);
    if (result == NULL)
	outofmem(__FILE__, "HTEscape");
    for (q = result, p = str; *p; p++) {
	unsigned char a = TOASCII(*p);
	if (a == 32) {
	    *q++ = '+';
	} else if (!ACCEPTABLE(a)) {
	    *q++ = HEX_ESCAPE;	/* Means hex commming */
	    *q++ = hex[a >> 4];
	    *q++ = hex[a & 15];
	} else {
	    *q++ = *p;
	}
    }
    *q++ = '\0';			/* Terminate */
    return result;
}

/*	Decode %xx escaped characters.				HTUnEscape()
**	------------------------------
**
**	This function takes a pointer to a string in which some
**	characters may have been encoded in %xy form, where xy is
**	the acsii hex code for character 16x+y.
**	The string is converted in place, as it will never grow.
*/
PRIVATE char from_hex ARGS1(
	char,		c)
{
    return (char) ( c >= '0' && c <= '9' ?  c - '0'
	    : c >= 'A' && c <= 'F'? c - 'A' + 10
	    : c - 'a' + 10);     /* accept small letters just in case */
}

PUBLIC char * HTUnEscape ARGS1(
	char *,		str)
{
    char * p = str;
    char * q = str;

    if (!(p && *p))
	return str;

    while (*p != '\0') {
	if (*p == HEX_ESCAPE &&
	    /*
	     *	Tests shouldn't be needed, but better safe than sorry.
	     */
	    p[1] && p[2] &&
	    isxdigit(UCH(p[1])) &&
	    isxdigit(UCH(p[2]))) {
	    p++;
	    if (*p)
		*q = (char) (from_hex(*p++) * 16);
	    if (*p) {
		/*
		** Careful! FROMASCII() may evaluate its arg more than once!
		*/  /* S/390 -- gil -- 0221 */
		*q = (char) (*q + from_hex(*p++));
	    }
	    *q = FROMASCII(*q);
	    q++;
	} else {
	    *q++ = *p++;
	}
    }

    *q++ = '\0';
    return str;

} /* HTUnEscape */

/*	Decode some %xx escaped characters.		      HTUnEscapeSome()
**	-----------------------------------			Klaus Weide
**							    ([e-mail])
**	This function takes a pointer to a string in which some
**	characters may have been encoded in %xy form, where xy is
**	the acsii hex code for character 16x+y, and a pointer to
**	a second string containing one or more characters which
**	should be unescaped if escaped in the first string.
**	The first string is converted in place, as it will never grow.
*/
PUBLIC char * HTUnEscapeSome ARGS2(
	char *,		str,
	CONST char *,	do_trans)
{
    char * p = str;
    char * q = str;
    char testcode;

    if (p == NULL || *p == '\0' || do_trans == NULL || *do_trans == '\0')
	return str;

    while (*p != '\0') {
	if (*p == HEX_ESCAPE &&
	    p[1] && p[2] &&	/* tests shouldn't be needed, but.. */
	    isxdigit(UCH(p[1])) &&
	    isxdigit(UCH(p[2])) &&
	    (testcode = (char) FROMASCII(from_hex(p[1])*16 +
		from_hex(p[2]))) && /* %00 no good*/
	    strchr(do_trans, testcode)) { /* it's one of the ones we want */
	    *q++ = testcode;
	    p += 3;
	} else {
	    *q++ = *p++;
	}
    }

    *q++ = '\0';
    return str;

} /* HTUnEscapeSome */

PRIVATE CONST unsigned char crfc[96] =

/*	Bit 0		xalpha		-- need "quoting"
**	Bit 1		xpalpha		-- need \escape if quoted
*/
    /*	 0 1 2 3 4 5 6 7 8 9 A B C D E F */
    {	 1,0,3,0,0,0,0,0,1,1,0,0,1,0,1,0,	/* 2x	!"#$%&'()*+,-./  */
	 0,0,0,0,0,0,0,0,0,0,1,1,1,0,1,0,	/* 3x  0123456789:;<=>?  */
	 1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,	/* 4x  @ABCDEFGHIJKLMNO  */
	 0,0,0,0,0,0,0,0,0,0,0,1,2,1,0,0,	/* 5X  PQRSTUVWXYZ[\]^_  */
	 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,	/* 6x  `abcdefghijklmno  */
	 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3 };	/* 7X  pqrstuvwxyz{|}~	DEL */

/*
**  Turn a string which is not a RFC 822 token into a quoted-string. - KW
*/
PUBLIC void HTMake822Word ARGS1(
	char **,	str)
{
    CONST char * p;
    char * q;
    char * result;
    unsigned char a;
    int added = 0;
    if (!(*str) || !(**str)) {
	StrAllocCopy(*str, "\"\"");
	return;
    }
    for (p = *str; *p; p++) {
	a = TOASCII(*p);  /* S/390 -- gil -- 0240 */
	if (a < 32 || a >= 128 ||
	    ((crfc[a-32]) & 1)) {
	    if (!added)
		added = 2;
	    if (a >= 160 || a == '\t')
		continue;
	    if (a == '\r' || a == '\n')
		added += 2;
	    else if ((a & 127) < 32 || ((crfc[a-32]) & 2))
		added++;
	}
    }
    if (!added)
	return;
    result = typecallocn(char, p-(*str) + added + 1);
    if (result == NULL)
	outofmem(__FILE__, "HTMake822Word");
    result[0] = '"';
    /*
    ** Having converted the character to ASCII, we can't use symbolic
    ** escape codes, since they're in the host character set, which
    ** is not necessarily ASCII.  Thus we use octal escape codes instead.
    ** -- gil (Paul Gilmartin) <[e-mail]>
    */  /* S/390 -- gil -- 0268 */
    for (q = result + 1, p = *str; *p; p++) {
	a = TOASCII(*p);
	if ((a != '\011') && ((a & 127) < 32 ||
			    ( a < 128 && ((crfc[a-32]) & 2))))
	    *q++ = '\033';
	*q++ = *p;
	if (a == '\012' || (a == '\015' && (TOASCII(*(p+1)) != '\012')))
	    *q++ = ' ';
    }
    *q++ = '"';
    *q++ = '\0';			/* Terminate */
    FREE(*str);
    *str = result;
}